Mineral Occurrence of Molybdenum at El Teniente, Chile: Implications to Metallurgical Recovery

摘要

The El Teniente Cu-Mo deposit is one of the world's largest porphyry ore deposits. Molybdenum is the second most important resource in the exploitation process. Despite this, there is little information available about the geological and mineralogical features of this metal, which would allow for maximizing metallurgical recovery. In this context a geological and mineralogical characterization of molybdenum was performed in the El Teniente deposit. The obtained results are presented in this paper and will be incorporated in the 2019 molybdenum recovery geometallurgical model.A database of 1254 rock samples from diverse sectors of the deposit containing geochemical, metallurgical and mineralogical information was use to perform various analysis to determine relevant correlations between molybdenum recovery and other existing parameters such as Mo Grade. Mineral characterization was carried out over a total of a hundred drill core segments, to establish the mineral occurrence of molybdenite and other molybdenum bearing minerals. Twelve molybdenite mineralization styles were classified according to the different hydrothermal alteration events associated. The influence of geological factors such as rock lithology, hypogene/supergene mineralization zone and hydrothermal alteration affecting the flotation recovery of molybdenum was studied. It was determined that 75 % of the molybdenum mineralization has its origin associated with the late magmatic alteration stage, while 25 % is associated to the late hydrothermal alteration stage of the porphyry copper system. The supergene enrichment zone has the worst grades and recovery of Mo in the deposit. It is concluded that the geological features that were studied present a control over the molybdenum recovery and its influence is reflected in several variables such as Mo grade, molybdenite grain size, liberation grade and mineral association. Finally, it is established that molybdenite which mineralization occurred in late magmatic events, predominantly has a better Mo recovery in the flotation process than late hydrothermal molybdenite.